rrule/src/datetime.ts

import { ParsedOptions, Frequency } from './types'
import { pymod, divmod, empty, includes } from './helpers'
import { getWeekday, MAXYEAR, monthRange } from './dateutil'

export class Time {
  public hour: number
  public minute: number
  public second: number
  public millisecond: number

  constructor(
    hour: number,
    minute: number,
    second: number,
    millisecond: number
  ) {
    this.hour = hour
    this.minute = minute
    this.second = second
    this.millisecond = millisecond || 0
  }

  getHours() {
    return this.hour
  }

  getMinutes() {
    return this.minute
  }

  getSeconds() {
    return this.second
  }

  getMilliseconds() {
    return this.millisecond
  }

  getTime() {
    return (
      (this.hour * 60 * 60 + this.minute * 60 + this.second) * 1000 +
      this.millisecond
    )
  }
}

export class DateTime extends Time {
  public day: number
  public month: number
  public year: number

  static fromDate(date: Date) {
    return new this(
      date.getUTCFullYear(),
      date.getUTCMonth() + 1,
      date.getUTCDate(),
      date.getUTCHours(),
      date.getUTCMinutes(),
      date.getUTCSeconds(),
      date.valueOf() % 1000
    )
  }

  constructor(
    year: number,
    month: number,
    day: number,
    hour: number,
    minute: number,
    second: number,
    millisecond: number
  ) {
    super(hour, minute, second, millisecond)
    this.year = year
    this.month = month
    this.day = day
  }

  getWeekday() {
    return getWeekday(new Date(this.getTime()))
  }

  getTime() {
    return new Date(
      Date.UTC(
        this.year,
        this.month - 1,
        this.day,
        this.hour,
        this.minute,
        this.second,
        this.millisecond
      )
    ).getTime()
  }

  getDay() {
    return this.day
  }

  getMonth() {
    return this.month
  }

  getYear() {
    return this.year
  }

  public addYears(years: number) {
    this.year += years
  }

  public addMonths(months: number) {
    this.month += months
    if (this.month > 12) {
      const yearDiv = Math.floor(this.month / 12)
      const monthMod = pymod(this.month, 12)
      this.month = monthMod
      this.year += yearDiv
      if (this.month === 0) {
        this.month = 12
        --this.year
      }
    }
  }

  public addWeekly(days: number, wkst: number) {
    if (wkst > this.getWeekday()) {
      this.day += -(this.getWeekday() + 1 + (6 - wkst)) + days * 7
    } else {
      this.day += -(this.getWeekday() - wkst) + days * 7
    }

    this.fixDay()
  }

  public addDaily(days: number) {
    this.day += days
    this.fixDay()
  }

  public addHours(hours: number, filtered: boolean, byhour: number[]) {
    if (filtered) {
      // Jump to one iteration before next day
      this.hour += Math.floor((23 - this.hour) / hours) * hours
    }

    for (;;) {
      this.hour += hours
      const { div: dayDiv, mod: hourMod } = divmod(this.hour, 24)
      if (dayDiv) {
        this.hour = hourMod
        this.addDaily(dayDiv)
      }

      if (empty(byhour) || includes(byhour, this.hour)) break
    }
  }

  public addMinutes(
    minutes: number,
    filtered: boolean,
    byhour: number[],
    byminute: number[]
  ) {
    if (filtered) {
      // Jump to one iteration before next day
      this.minute +=
        Math.floor((1439 - (this.hour * 60 + this.minute)) / minutes) * minutes
    }

    for (;;) {
      this.minute += minutes
      const { div: hourDiv, mod: minuteMod } = divmod(this.minute, 60)
      if (hourDiv) {
        this.minute = minuteMod
        this.addHours(hourDiv, false, byhour)
      }

      if (
        (empty(byhour) || includes(byhour, this.hour)) &&
        (empty(byminute) || includes(byminute, this.minute))
      ) {
        break
      }
    }
  }

  public addSeconds(
    seconds: number,
    filtered: boolean,
    byhour: number[],
    byminute: number[],
    bysecond: number[]
  ) {
    if (filtered) {
      // Jump to one iteration before next day
      this.second +=
        Math.floor(
          (86399 - (this.hour * 3600 + this.minute * 60 + this.second)) /
            seconds
        ) * seconds
    }

    for (;;) {
      this.second += seconds
      const { div: minuteDiv, mod: secondMod } = divmod(this.second, 60)
      if (minuteDiv) {
        this.second = secondMod
        this.addMinutes(minuteDiv, false, byhour, byminute)
      }

      if (
        (empty(byhour) || includes(byhour, this.hour)) &&
        (empty(byminute) || includes(byminute, this.minute)) &&
        (empty(bysecond) || includes(bysecond, this.second))
      ) {
        break
      }
    }
  }

  public fixDay() {
    if (this.day <= 28) {
      return
    }

    let daysinmonth = monthRange(this.year, this.month - 1)[1]
    if (this.day <= daysinmonth) {
      return
    }

    while (this.day > daysinmonth) {
      this.day -= daysinmonth
      ++this.month
      if (this.month === 13) {
        this.month = 1
        ++this.year
        if (this.year > MAXYEAR) {
          return
        }
      }

      daysinmonth = monthRange(this.year, this.month - 1)[1]
    }
  }

  public add(options: ParsedOptions, filtered: boolean) {
    const { freq, interval, wkst, byhour, byminute, bysecond } = options

    switch (freq) {
      case Frequency.YEARLY:
        return this.addYears(interval)
      case Frequency.MONTHLY:
        return this.addMonths(interval)
      case Frequency.WEEKLY:
        return this.addWeekly(interval, wkst)
      case Frequency.DAILY:
        return this.addDaily(interval)
      case Frequency.HOURLY:
        return this.addHours(interval, filtered, byhour)
      case Frequency.MINUTELY:
        return this.addMinutes(interval, filtered, byhour, byminute)
      case Frequency.SECONDLY:
        return this.addSeconds(interval, filtered, byhour, byminute, bysecond)
    }
  }
}